绝 = cut off, 圣 = the holy, the sacred, 弃 = abandon, 智 = wisdom
绝圣弃智 = Discarding the conventional wisdom that is held holy and sacred
It is a controversial philosophy and I will use a controversial example: Discarding the Bible (the conventional wisdom that is held holy and sacred) is a 绝圣弃智的行径.

So you want to say it's kind of defiant act, maybe even resulting in profanation?

Click to expand...

Erm, it depends on the context and on one's belief/value system. It is a controversial behavior for sure. The right wing (e.g.,Confucianists) may regard the left (e.g., Daoists) as desecrators or "infidels" (for lack of a better word).
绝圣弃智 is a Daoist philosophy by the way.

Thank you for clarifications. Actually, the original context of this chenyu was this small story, take a look. As you can see, there's not a single religious connotation in it, that's why I was perplexed in the first place

I think your understanding in the OP is generally correct. 绝圣弃智 is not so extreme as "defiant act" or "profanation".
绝 and 弃 have similar meanings: 绝-- to refuse; 弃-- to discard, to throw away
圣 and 智 have similar meanings: 圣-- something/someone high esteemed; 智--wisdom
So I would say its general meaning is "to refuse the authority, not to believe in any 'wisdom' blindly".

I've read that story, and I think the meaning of 绝圣弃智 here is a bit different from its original meaning.
In the story, it says the young is only focusing on fishing but ignores the wonderful surrounding scenery, and this "ignorance" is 绝圣弃智(so, "to ignore/pay no attention to the beautiful scenery"); in contrast, the old fisherman enjoys the scenery a lot rather than simply focusing on fishing. So the author is encouraging the old fisherman's wisdom/attitude towards life.

In its simplest interpretation, "绝圣弃智" means "abandoning what is considered sacred, discarding what is held as wisdom".
This is of course seen as a good or bad thing to do depending on one's point of view.

绝圣弃智 = Discarding the conventional wisdom that is held holy and sacred

Click to expand...

Hi! 聖智 isn't really about "conventional wisdom held holy and sacred", but is more like "shrewdness/craftiness/canniness". The particular expression comes from part 19 of 老子 (絕聖棄智 民利百倍), and in part 18 you can read: 慧智出 有大偽. The meaning of 聖智 is just like 慧智, which, according to Taoist philosophy, causes nothing but frauds. The motif is repeated many times in 老子 (e.g. part 65: 民之難治 以其智多), and is much elaborated in 莊子‧胠篋.

As Lucia hints at above, the author of the story is probably making fun of the young angler, who is only caring his own business and paying no attention to the lovely scenery around him, thus conforming to the Taoist ideal in his "clueless" state (老子 part 20: 俗人昭昭 我獨昏昏 俗人察察 我獨悶悶).

Thank you for your help. May I ask just one more question, also originating from the same story about a fisherman?

A little bit later the author says: 老渔翁收了一串子母钩儿，上边有四尾活泼刺刺的鳟鱼.
Old angler collected his fishing hooks and other tackle in one bunch, there were four live trouts on top of it (?)
I don't quite understand what is 一串子母钩儿 here. Is this some big and small kinds of fishing hooks?

老渔翁收了一串子母钩儿，上边有四尾活泼刺刺的鳟鱼...I don't quite understand what is 一串子母钩儿 here. Is this some big and small kinds of fishing hooks?

Click to expand...

子母钩 = double-hook rig. 母 denotes the hook with a bait, 子 the other without a bait.
四尾活泼刺刺的鳟鱼 four trout on a two-hook rig? It seems impossible.
I guess 一串子母钩 = multiple-hook rig. One 母 + multiple 子 (baitless).

I don't know fishing, but "子母something" is a tradition way of naming something combined by two similar parts: one bigger (major) and one smaller (minor).

Click to expand...

Yes, as I'm being told, 子母钩 is a type of fishing hook, with a small hook attached to a bigger hook usually used to catch big fish.

If I may ask just one more question, I'd like you to pay attention to this sentence (from the same story):

直等鱼儿钻到水底.
He is waiting for the fish to come down to the bottom of the river.
倏然溜走，牵动了钓竿，老渔翁这才伸手下去把钓丝拉回来。
Suddenly it's almost gone, having just touched the fishing rod (line?), and only then the old fisherman reach out his hand to pull out the line.

I'm not quite sure of the meaning of 倏然溜走，牵动了钓竿. Does it relate to a fish that has almost escaped the hooks?